Id say its a number of things, for one boys upbringing is very different to girls, girls are often expected to be nurturing and giving, boys are often reared to repress their emotions and get away with violent and sexual behaviors that girls would never get away with.
If a girl is openly sexual or chases after a boy, shes called crazy and a slut. If a boy chases after a girl he's seen as romantic and a bit of a stud. If a girl or woman isnt interested in a man that's interested in her, and she refuses to date him or stops dating him, she's a bitch - regardless of the reasons for turning him down, she's still the one that comes out looking bad. If a man breaks up with a woman, she's still the one that comes out looking bad - she must be crazy or a bitch.
If a man has sex early on in dating someone its no problem, if a woman does, she's seen as having no respect for herself.
On the other hand womens sexuality is exploited through advertising, porn and prostitution, women are treated as commodities, sending unhealthy messages to men about women and sex.
The cultural views of men and women create an imbalance were men can feel entitled to sex and women feel they have to repress their sexuality or face the consequences of being a called a slut and treated accordingly.
Neither approach to sex or gender is healthy and I understand the term toxic masculinity is frowned upon on this site in particular, it gets a few backs up but personally I feel it is an issue within all societies and cultures and our views towards men and women have allot to do with it.
I also think testosterone plays a part as it makes people more aggressive but also, mental illnesses like psychopathy is more common in men, whether its under-diagnosed in women and potentially effects them differently could be a reason for the statistical gender imbalance for psychopaths, often times research is only carried out in men and not women so there's not much to go on as to how or why mental illness and disability effect men and women differently.
Also, there probably is a number of instances where the women are perpetrates that go unreported, that said theres allot of unreported instances were men are the perpetrates too so its hard to say.
Generally though, men are the cause of most of the violence and sexual abuse that happens world over, in every culture through out history. Thats not an attack on men, and its not an attack on any man that is reading this, its a basic fact and just because the majority of violence is caused by men that doesn't mean the majority of men are violent.
Keep in mind that the majority of male victims of violence and sex abuse are abused by other men, its an issue that effects everyone and denying it and getting defensive about it doesnt do any good or help anyone.